MONDAY, June 3 (HealthDay News) -- As the number of adults taking prescription drugs has grown, so has the number of children being accidentally poisoned by them, a new study finds.

"We found between 2000 and 2009 [that] rates of pediatric exposure to adult medications were increasing," said lead researcher Dr. Lindsey Burghardt, from the division of emergency medicine at Boston Children's Hospital.

In addition, there was an association between the number of prescriptions written for these medications for adults and the increase in the number of children being poisoned by them, she said.

"This is the first step, to identify the extent of the problem," Burghardt said. "Despite all these precautions that have been put in place to try to prevent these poisonings in kids the problem persists," she said. "In fact, the number of poisonings has been increasing."

The next step is to try to identify why this is happening, Burghardt said. That, however, isn't clear at this point, she added.

Burghardt advises keeping these medications out of the reach of young children. Particularly, those under 5 who are at the greatest risk.

The greatest risk for teen misuse is from narcotic painkillers, Burghardt said, mostly intended for recreational use or to attempt suicide.

The report was published in the June 3 online edition of Pediatrics.

"What we see a lot is open prescription bottles from parents or grandparents, and ingestion of diabetic and other drugs by kids," said Dr. Vincenzo Maniaci, a pediatric emergency medicine doctor at Miami Children's Hospital. "Kids are going to get into everything."

Medications need to be kept high up, in locked boxes, so children can't get at them, Maniaci said. Medications should not be kept on countertops, in purses or on nightstands.

If a parent suspects a child had ingested a prescription medication, the first step is to call poison control, Maniaci said.

To try to get a handle on the extent of the problem, Burghardt's team used the National Poison Data System surveys for 2000 through 2009 to track poisoning from prescription drugs among infants to 5-year-olds, children aged 6 to 12 and teens aged 13 to 19.

They found young children had the greatest risk of being poisoned by diabetes drugs (60.2 percent) and blood pressure drugs (59.7 percent).

The most serious injuries and hospitalizations, however, were cause by narcotic painkillers and diabetes drugs.

Prescription pills aren't the only drugs kids are finding and taking. A recent study in the online edition of JAMA Pediatrics found that since medical marijuana was legalized in Colorado, more than a dozen young children have been unintentionally poisoned with the drug.

About half of the cases resulted from kids eating marijuana-laced cookies, brownies, sodas or candy. In many cases, the marijuana came from their grandparents' stash, the investigators said.

But doctors aren't familiar with marijuana poisoning in children, so unless the parents are forthcoming it can take time and tests to diagnose the problem, the Colorado researchers explained. Symptoms of marijuana poisoning in children include sleepiness and balance problems while walking.